• The Journal of Korean Institute of Communications and Information Sciences
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• v.7 no.2
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• pp.71-77
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• 1982

This poper proposes the method of the balanced-mixer realization in the X-Band frequency range by the MIC coplanar magic-tee. This magic-tee is composed with microstrip and slot, as suggested by Ronde. The characteristics of balancing and isolation in this magic-tee is more preferable to those of the rat-race or hybrid ring in the wide frequency range. So, experimentally in this paper the characteristics of the MIC balanced-mixed are obtained with the VSWR less than 1, 2(in Local and Signal Arms) and the Conversion Loss, 6 dB in that frequency range, when the mixer is designed in the 3rd order (in E-arm) and 2nd order(in H-arm) Chebyshev matching networks, and with two symmetrical Schottkey Barrier Diodes.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.2
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• pp.104-115
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• 2002

Core is the main component of inductor. This core should be classified into around 10 classes according to the value of inductance and Q. The coil should be winded with the outer-boundary of this core by different number of turns. Theses kind of precise inductors would be required in the future environment which PCs and communication devices demand more high speed and lower voltage level. It would be quite unefficient that only one core is classified once a time. There, it will be developed so that 10 cores are classified simultaneously. For the operation of classifying 10 cores once in a time, suppose 10 test instruments could be used. In this case, it would take much cost since a test instrument Is expensive. So, by using only one test instrument, it is really more desirable that this system is developed. Each core classified by 10 different classes is to be stored into the corresponding box through the corresponding rubber hose. 10 cores are passed on a serial line and are placed on each testing slot. Here, each core located at each slot is tested, and then the bowl located on the top of a step motor is moved into the corresponding spot by rotating step motor with some angles. Each bowl connected with the corresponding box through rubber hose. Actually 100 hoses are connected, 10 step motors are rotated at 10 different angles, so the size is really so big, the shape of connecting 100 hoses is so complicated. Therefore it is anticipated that the system would be going to be easily out of ordered. In this paper the main purpose is to make several suggestions to be able to work well in these kinds of being affected by the abnormal operation of motors and the flow of cores.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.8
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• pp.1759-1764
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• 2015

In this paper, we considered a design method of a circular polarization (CP) antenna for UHF (ultra high frequency) RFID (Radio Frequency IDentification) readers. The antenna is a dual-fed circular microstrip patch which produces right-handed CP. Quadrature hybrid coupler is used for dual feeding. The outputs of the coupler and circular patch are connected through copper wires, and the inductive reactance produced by the connecting wires is compensated by a ring-shaped slot inserted inside the circular patch. The effects of the geometrical parameters of the proposed antenna on the antenna performance are examined, and the parameters are adjusted to be suitable for the operation in North American UHF RFID band (902-928 MHz), which includes domestic UHF RFID band. The antenna is fabricated, and the experiment results reveal a frequency band of 854-993 MHz for a voltage standing wave ratio < 2. The fabricated antenna is connected to a commercial RFID reader, and it showed a good performance of tag identification.

• Journal of Navigation and Port Research
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• v.38 no.4
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• pp.367-371
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• 2014

When the crew or passengers fall into the water due to marine accident of vessel, it is very important to rescue them quickly. In the case of marine accidents, most people in distress have been wearing a lifejacket, so if the GPS and Cospas-Sarsat communication module will be integrated within the lifejacket, it is easy to rescue them. In this paper, development of the dual band lifejacket-integrated antenna for GPS and Cospas-Sarsat communication is discussed. The antenna with the FR-4 substrate of 0.2mm thickness for flexibility was designed that it can be fitted close to the shoulder of the life jacket and operate at 1.575GHz and 406MHz. The GPS communication antenna was implemented with a ring-slot antenna having a circular polarized characteristic and a meander type linear polarized antenna is used as Cospas-Sarsat communication. The two antennas are fed by a single microstrip line and an open stub is used to minimize the mutual interference between the two antennas. The performance of the fabricated antenna attached to the life vest is confirmed by the measurement of the return loss at GPS and Cospas-Sarsat frequency bands.